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Grain yields tumble in greenhouse world

By FRED PEARCE

Dried-up fields and empty grain stores are likely to become semipermanent
features across much of the Third World by the middle of the next century,
according to an analysis of the likely impact of global warming presented
to the UN this week. Thecrippling drought in Southern Africathis year provides
a graphic foretaste of things to come.

The new study suggests a decline of between 10 and 15 per cent in grain
yields in Africa, tropical Latin America and much of India and Southeast
Asia, as well as a substantial increase in famine. Its author is Martin
Parry, director of the Environmental Change Unit at the University of Oxford
and a leading analyst of the agricultural implications of the greenhouse
effect.

Most of the world’s important food crops, including wheat, rice, soya
beans, sorghum and millet, will be hit, says Parry. His study assesses the
implications of regional changes in climate predicted by computer models
run by Britain’s Meteorological Office and NASA’s Goddard Institute of Space
Studies (GISS) in the US. The models assume a doubling of carbon dioxide
concentrations in the atmosphere.

The two models differ over what might happen to crops in the richer
northern countries. While the GISS model suggests that crop yields could
increase in places as hotter summers become more frequent in the temperate
regions, the Met Office model suggests abandoned fields and declining harvests,
especially in North America.

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This finding contradicts recent studies presented to the White House
by American agriculturalists, which suggest that US agri-culture will be
largely immune to damage from global warming. These studies have helped
to convince the Bush administration not to back calls for national limits
on the production of greenhouse gases.

Declining yields in North America could have a worldwide impact, says
Parry. ‘Negative yield changes in North America would substantially raise
grain prices worldwide,’ he said in Oxford, before leaving for the US to
deliver his findings.

Parry is the author of a series of case studies on agriculture and the
greenhouse effect, published two years ago by the International Institute
for Applied Systems Analysis (IIASA). Since then he has become increasingly
pessimistic: ‘The change is much more negative than I had previously guessed.’

Predictions based on the Met Office climate model suggest, ‘a rise of
400 million in the number of people at risk from hunger’, he says. This,
according to a model of the world economy developed by IIASA, would increase
the number of people at risk to more than a billion within 50 years – one
in eight of the world’s likely population by that time.

Parry’s new findings follow a year’s work for the UN’s Intergovernmental
Panel on Climate Change. He stresses that they are not firm predictions,
but are ‘sensitivity studies’. They show the vulnerability of the world’s
farms to climate change. The projections, he says, build in the ability
of farming people to adapt to climate change by changing crops or farming
methods.

To prevent hunger, the world must make breakthroughs in biotechnology,
he says, creating new crops adapted to hotter climates and drier soils.
There will also be a need for ‘major, and I mean very major,irrigation and
land reclamation schemes’. But, he adds, ‘the best way of adapting would
be to reduce population growth’.

Parry’s studies also suggest that there will be increased demand for
water to irrigate fields in most of Europe. In the southeast of England,
where water supplies are stretched to the limit this year by the worst drought
for a century, demand could double within 50 years. His projections will
add urgency to calls for massive water transfer projects that could bring
water from the wet hillsides of Scotland and Wales to the increasingly dry
and heavily populated southeast.

Parry revealed some of his findings at a meeting at Green College, Oxford,
earlier this month. At the same meeting, Norman Myers, a British environment
consultant, presented preliminary calculations that rising sea levels and
declining farm yields could turn more than 300 million people into ‘environmental
refugees’ within 40 years.

Two out of three of the world’s cities with more than 2.5 million people
are on the coast, he said. Tens of millions of farmers could be forced from
large river deltas, such as the Nile, Yangtze, Mekong, Indus and the combined
delta of the Ganges and Brahmaputra, where some 100 million Bangladeshis
live. The threat of salt water invading fresh water aquifers, from which
farmers irrigate crops, is as great as the risk of inundation.

Myers is compiling a report on environmental migrants for the European
Commission on migration. ‘They are currently worried about people coming
from Eastern Europe and North Africa. But this is just a small part of the
problem. The world faces a totally unprecedented migration, 40 times greater
than those at the end of the Second World War.’

Myers predicts that the main routes for environmental migrants will
be across the Mediterranean, from Central to North America, from China to
Russia and from Southeast Asia to Australia.

Brian Walker, a former head of Oxfam, said: ‘While political and economic
refugees are usually small groups that can be assimilated, and may eventually
go home, environmental refugees will never go back. This will be something
irreversible.’

John Topping, President of the Climate Institute in Washington DC, added:
‘Governments often think they can ignore these issues, but environmental
change will bring political instability and even terrorism.’

New Zealand, said Topping, is already concerned that it might have to
accept refugees from low-lying Pacific islands that become uninhabitable
as sea levels rise. ‘If 15 or 20 countries just disappear, we may have to
look at the possibility of setting up entirely new countries,’ he said.